911mhawk

Wondering if others here have had the same experience where after a good hard 30 minutes of driving your ABS quits?
Typically we run 20 minute sessions with a 20-40 minute break between depending on amount of drivers/skill classes.
When I do just the lunch hour I'll run a little longer and usually it's a faster group and with no DE traffic so you can have several fast laps back to back.
A couple times last year, and again yesterday, I get the ABS warning light and don't have ABS. Drive a little w/o it for fun, realize it's nice to have when slowing from 150>75, then go park it for 10 minutes and back out with ABS working fine again. PSM is unplugged at the pump and car has 380/350 brakes on NT-01s that are at the sweet point (1/2 done).

Carlo_Carrera

911mhawk

​​​​​I think you nailed it, thanks.
Fluid is right at top full Mark when cold. I need to take a little out.

jumper5836

I had the same issue with levels either too low or just at the max. My local track has a lot of elevation changes and seems to get triggered.

Third-Reef

If is is caused by fluid levels with there be a error code stating fluid level, or just the ABS failure code?

Jut wondering because i have had this happen at the track also

powdrhound

Fluid near the full mark (when cold) with typically trigger a "low brake fluid" warning at the track when the fluid expands and goes above full. You want to set the fluid level near minimum or no higher than between the low/high marks for track use. I've never seen too much fluid trigger an ABS failure however.

kentburlingame

Experienced this from time to time starting 2-ish years ago (approx. 10-15 track days a year), and just last year my ABS module wound up failing (not a cheap replacement) at the last track I want to lose brakes (Oregon Raceway Park -- strongly suggest it sometime, Mark). It may be an early sign of that, but I'm not sure how one goes about checking it. If it is that, there have been many iterations to the ABS module since the cars were released, and the most current revision requires a new accelerometer and additional brackets for the accelerometer as well.

jumper5836

Wierd my ABS pump developed a leak and I had to replace the whole unit which as not cheap. I was seeing this ABS warning at the track as well. The unit I got came out of a 04 part number 996-255-955-58 and updated part number vs what the original 01 part number, hoping it doesn't happen again but I still get the warning at the track sometimes with levels either too low or just at the max.

911mhawk

I'll be at the track again in April if it's dry and plan to pull a little fluid from the reservoir to see if it still happens.
I didn't get any fluid warning, just ABS failure...
Lots of elevation like Jumper's so maybe that causes it too...
Wasn't an issue this past Saturday on street tires but I only run them if there's water on the track.

kentburlingame

I've yet to have the car back on track since the module popped, as I'm waiting to get a transmission cooler installed before getting back out there (last year was not kind to my wallet). I'm hoping it was just a one-time occurrence myself, but I've found the car has been great on the street since for what it's worth.

Mark, since you're investigating whether it may be fluid-level related, it begs the question... what brake fluid are you running? Maybe it's expanding more, possibly overflowing in the reservoir. I've stuck with the Motul RBF600 as it seems to hold up really well with the PNW climate, allows for pretty aggressive sessions with the high boiling point, and, to my knowledge, I didn't have issues with the fluid level causing the ABS failure (though I suppose it could have led to the module failure). Most folks I track with run the same, with a few going above and beyond for the Castrol SRF.

911mhawk

To update this thread, Brembo HTC64T is what I've used last 2 years with no complaint (this and Endless were the only 2 used in F1 as of a year or two ago and Endless is used by Cup cars).

The past 2 track outings I did not have any ABS issue despite trying to replicate the concern by driving hard for longer session until tires were going off. I did notice a small amount of fluid in the rim of the reservoir and will remove a little fluid before my next outing to see if it happens again. The cap and reservoir are new and on tight.

Regarding 600/660, IveI run them both and they suck compared to the Brembo HTC64T. You have to bleed those after every full day, Brembo fluid goes a long long time. Haven't tried Endless yet.